[api] Default native data property setter to replace the setter if the property is writable.

src/lookup.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_LOOKUP_H_
 #define V8_LOOKUP_H_
 
 #include "src/factory.h"
 #include "src/isolate.h"
 #include "src/objects.h"
@@ skipping 219 matching lines @@
   void Delete();
   void TransitionToAccessorProperty(AccessorComponent component,
                                     Handle<Object> accessor,
                                     PropertyAttributes attributes);
   void TransitionToAccessorPair(Handle<Object> pair,
                                 PropertyAttributes attributes);
   PropertyDetails property_details() const {
     DCHECK(has_property_);
     return property_details_;
   }
+  PropertyAttributes property_attributes() const {
+    return property_details().attributes();
+  }
   bool IsConfigurable() const { return property_details().IsConfigurable(); }
   bool IsReadOnly() const { return property_details().IsReadOnly(); }
   Representation representation() const {
     return property_details().representation();
   }
   FieldIndex GetFieldIndex() const;
   Handle<HeapType> GetFieldType() const;
   int GetAccessorIndex() const;
   int GetConstantIndex() const;
   Handle<PropertyCell> GetPropertyCell() const;
@@ skipping 87 matching lines @@
   Handle<Map> holder_map_;
   const Handle<JSReceiver> initial_holder_;
   uint32_t number_;
 };
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_LOOKUP_H_